The present invention relates to a paging receiver with a display function which allows an ordinary message to be displayed and a receiver control signal to be transmitted and received together in the form of a single message.
With a prior art paging receiver having with a display function, it has been customary to separately send a conventional message to be displayed and a receiver control signal which is adapted for the registration and deletion of an address for the reception of information, alert control or similar purposes. That is, it has been impractical to send them together in a single message format. An example of a paging receiver of the kind described is disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 62-239726 (corresponding to U.S. patent application Ser. No. 035,348, European Patent Application No. 87303013.4, Canadian Patent Application No. 534,391, Australian Patent Application No. 71377/87, Korean Patent Application No. 3486/1987, and Taiwan Patent Application No. 76101975).
The paging receiver disclosed in this Patent Publication is capable of receiving a call number assigned to that receiver (A call) and another call number adapted for an information service which is available for a number of unspecified receivers (B call). The receiver is allowed to or inhibited from receiving the information survice which is based on the B call to a group of unspecified receivers, depending upon whether or not it detects a predetermined pattern (e.g. "space", "+" or "-") in a message which is added to the A call. More specifically, the receiver displays a message such as "OUT SERVICE" when the receiver is inhibited from receiving the information service and a message such as "IN SERVICE" when it is allowed to receive it.
As stated above, with a prior art paging receiver having a display function, it is impossible to send a receiver control signal and a conventional message in the form of a single composite message. For example, when a subscriber who owns the receiver is excluded from an information service, a message notifying the subscriber of the inhibition of reception of the information service such as "INFORMATION SERVICE XX NOT OFFERED. FOR DETAILS, CALL XX-XXXX. X MONTH X DAY XX SERVICE CORP." cannot be sent together with a receiver control signal which disables the receiver from receiving the service. On the other hand, since a different pattern has to be pre-assigned to each receiver control function, it is difficult to provide the receiver with an extra control function after an information service has been initiated. For example, assume that only the receiver control function for "allowing and inhibiting the reception of an information service" is available with the receiver at the beginning of the service. Then, when an extra function of "energizing a speaker only when important information is supplied" is provided in addition to the above-mentioned receiver control function after the start of the service, the old version receiver fails to recognize a receiver control signal representative of the extra function and therefore erroneously displays it as an ordinary message.